Isolating CDP from weak wood floor

My CDP skips (alot) when my 25lb son dances on the wood floor in front of it (weak joists). I have a solid Manna rack and use MIB bearings under the CDP, but there is really no up/down isolation. I've also tried nothing, bubble wrap and some thick rubber/cork feet--no dice. I just looked at some Solid-Tech discs of silence, which seem like they might work-http://solid-tech.net/isolator.htm. Before I shell out the $$, I thought I'd see if anyone else has faced this problem. Thanks. D